Fluidizing agents

ABSTRACT

A fluidizing agent which is a diamine and/or diquaternary ammonium salt of a coloured acid of the phthalocyanine or disazo series of dyestuffs wherein the diamine or diquaternary ammonium cation is of formula (1) wherein R is optionally substituted C 6-30 -alkyl or optionally substituted C 6-30 -alkenyl; R 1  is hydrogen, optionally substituted C 1-30 -alkyl or C 2-30 -alkenyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted aralkyl; R 2 , R 3  and R 5  are each, individually, optionally substituted C 1-6 -alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted aralkyl; R 4  is hydrogen, optionally substituted C 1-6 -alkyl, optionally substituted cycloalkyl, optionally substituted aryl or optionally substituted aralkyl; X is C 1-12 -alkylene or C 2-14 -alkenylene; or R 1  and R 3  together with the two nitrogen atoms to which they are attached and X form a ring; and/or R 4  and R 5  together with the nitrogen atom to which they are attached form a ring. Preferably, R is C 14-18 -alkyl, X is propylene and R 1  to R 5  is methyl.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase application based onPCT/GB00/03246, filed Aug. 23, 2000, and which further claims priorityfrom British Application No. 9920107.1, filed Aug. 26, 1999. Theseapplications in their entirety are incorporated herein by reference.

The present application relates to fluidising agents for reducing theviscosity of dispersions of a particulate solid such as a pigmentdispersed in an organic liquid using a dispersant and to millbases,paints and printing inks containing such fluidising agents.

U.S. Pat. No. 4,057,436 discloses a composition comprising a finelydivided solid, a polymeric or resinous dispersant, a fluidising agentwhich is a substituted ammonium salt of a coloured acid wherein thereare from 16 to 60 carbon atoms contained in at least 3 chains attachedto the N atom of the substituted ammonium cation and an organic liquid.These fluidising agents are stated to give dispersions which exhibitlower viscosity at higher pigment loadings compared with similardispersions which do not contain the fluidising agent. Examples ofsuitable amines and substituted ammonium salts which can be used to formthe fluidising agents are tertiary amines and quaternary substitutedammonium salts such as N,N-dimethyloctadecylamine, cetyl-trimethylammonium bromide, didodecyl dimethyl ammonium chloride, dioctadecyldimethyl ammonium chloride, N-cetyl pyridinium salts, N-cetylpiperidine, benzyldimethyloctadecyl ammonium chloride, octadecylbis-(2-hydroxyethyl)amine and3-(N-octadecyl-N-hydroxyethylamino)propyl-N¹,N¹-bis(2-hydroxyethyl)amine.The latter diamine is the only compound containing two tertiary nitrogenatoms which is disclosed. However, there are no specific examples ofdiamine salts of coloured acids and no advantage is envisaged for suchcompounds compared with those containing only the one tertiary nitrogenatom. The coloured acid used to make the fluidising agents includemono-, di- and tri-sulphonated copper phthalocyanine and azo andanthraquinone dyestuffs containing sulphonic acid and/or carboxylic acidgroups. These fluidising agents were found to be particularly effectivein dispersing a copper phthalocyanine pigment in an organic liquid. Thecopper phthalocyanine may be in crude or pigmentary form.

U.S. Pat. No. 4,461,647 discloses a fluidising agent which is acomposition of disazo compounds containing at least 30% by weight of awater-insoluble disazo compound comprising a central divalent group freefrom acid and other ionic substituents linked through azo groups to twomonovalent end groups characterised in that one end group, the first, isfree from acidic and other ionic substituents and the other end group,the second, carries a single substituted ammonium-acid salt group. Thesubstituted ammonium-acid salt group can be derived fromdioctadecyldimethyl ammonium chloride or hydroxide, hexadecyltrimethylammonium bromide, octadec-12-anyldimethylamine and dodecyltrimethylammonium chloride.

GB 1356253 discloses benzidine pigment compositions which are mixturesof benzidine pigments which are free from water-solubilising groups andbenzidine dyestuffs which contain two or more acid groups. The acidgroups may be in the form of amine salts of diamines. These benzidinepigment compositions are stated to give improved colour strength andtransparency when incorporated into printing inks compared withbenzidine pigments which contain no acid groups. Benzidine pigments areobtained by tetrazotising benzidine derivatives which are free fromwater-solubilising groups and coupling with 2 moles ofacetoacetarylamide or pyrazolone derivatives which are also free fromwater-solubilising groups. Benzidine dyestuffs containing two or moreacid groups have similar structures but contain either two sulphonicacid groups in the benzidine derivative and/or acid groups in each ofthe coupling components.

It has now been found that fluidising agents which are diamine ordiquaternary ammonium salts of coloured acids provide dispersions ofpigments in organic liquids which exhibit lower viscosity at highpigment loadings when the diamine or diquaternary ammonium compoundcontains two or more nitrogen atoms compared with those amines andquaternary ammonium compounds which contain only one nitrogen atom.

According to the invention there is provided a fluidising agent which isa diamine and/or diquaternary ammonium salt of a coloured acid whereinthe diamine or diquaternary ammonium cation contains two or morenitrogen atoms, except for fluidising agents which are diamine salts ofan N-long chain alkyl alkylene diamine and a benzidine dyestuffcontaining two or more acid groups.

Preferably, the diamine or diquaternary ammonium cation is of formula 1

wherein

R is optionally substituted C₆₋₃₀-alkyl or optionally substitutedC₆₋₃₀-alkenyl;

R¹ is hydrogen, optionally substituted C₁₋₃₀-alkyl or C₂₋₃₀-alkenyl,optionally substituted cycloalkyl, optionally substituted aryl oroptionally substituted aralkyl;

R², R³ and R⁵ are each, individually, optionally substituted C¹⁻⁶-alkyl,optionally substituted cycloalkyl, optionally substituted aryl oroptionally substituted aralkyl;

R⁴ is hydrogen, optionally substituted C₁₋₆-alkyl, optionallysubstituted cycloalkyl, optionally substituted aryl or optionallysubstituted aralkyl;

X is C₁₋₁₂-alkylene or C₂₋₁₄-alkenylene; or

R¹ and R³ together with the two nitrogen atoms to which they areattached and X form a ring; and/or

R⁴ and R⁵ together with the nitrogen atom to which they are attachedform a ring.

In the cation of formula 1, the hydrogen atoms represented by R¹ and/orR⁴ are derived from the coloured acid.

When R and R¹ is alkyl or alkenyl it may be linear or branched, but ispreferably linear.

When R to R⁵ are substituted, the substituent may be hydroxy,C₁₋₆-alkoxy, cyano or halogen. However, it is preferred that R to R⁵ areunsubstituted.

When R¹ is alkenyl it is preferably C₆₋₃₀-alkenyl.

When R¹ to R⁵ is aryl it is preferably phenyl and when R¹ to R⁵ isaralkyl, it is preferably benzyl or 2-phenylethyl.

When R¹ to R⁵ is substituted aryl or substituted aralkyl, thesubstituent is preferably hydroxy, C₁₋₄-alkoxy, cyano or halogen.

When R to R⁵ is substituted by halogen it is preferably bromine andespecially chlorine.

When R¹ to R⁵ is cycloalkyl it is preferably cyclopentyl or cyclohexyl.

When R¹ and R³ together with the two nitrogen atoms to which they areattached and X form a ring, the ring is preferably piperazinyl.

When R⁴ and R⁵ together with the nitrogen atom to which they areattached form a ring, the ring is preferably piperidinyl, morpholinyl,piperazinyl or N—C₁₋₆-alkylpiperazinyl.

When R¹ is optionally substituted C₁₋₃₀-alkyl it is preferablyoptionally substituted C₁₋₆-alkyl.

When R¹ to R⁵ is C₁₋₆-alkyl it may be linear or branched. Examples areethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-hexyl andespecially methyl.

It is preferred that the compound of formula 1 contains two nitrogenatoms.

When R¹ and R⁴ are both hydrogen, the compound of formula 1 is a diamineand it forms an amine salt with the coloured acid.

When R¹ and R⁴ are other than hydrogen the compound of formula 1 is adiquaternary ammonium cation and forms a quaternary ammonium salt withthe coloured acid.

Preferably X contains not less than 2 and especially not less than 3carbon atoms. It is also preferred that X contains not greater than 12,more preferably not greater than 8 and especially not greater than 4carbon atoms. Useful effects have been obtained when X is propylene.

In one preferred group of compounds of formula 1, R¹ and R⁴ are bothhydrogen and R², R³ and R⁵ are each, independently C₁₋₆-alkyl andespecially methyl.

In a more preferred group of compounds of formula 1, R¹ to R⁵ are each,independently, C₁₋₆-alkyl and especially methyl.

Preferably, R contains not less than 8 carbon atoms. It is alsopreferred that R contains not greater than 20 and especially not greaterthan 18 carbon atoms.

The diamines and diquaternary ammonium compounds of formula 1 may bederived from natural products and as such may be available commerciallyas mixtures of diamines and diquaternary ammonium compounds.Particularly useful mixtures are those derived from tallow. In suchmixtures, R is typically C₁₀₋₁₈-alkyl containing C₁₆-alkylene.

The total number of carbon atoms represented by R to R⁵ and X in thecompound of formula 1 is preferably not greater than 80, more preferablynot greater than 60, even more preferably not greater than 50 andespecially not greater than 30.

Especially useful fluidising agents have been obtained when the compoundof formula 1 is N—(C₁₄₋₁₈-alkyl)-N,N,N′,N′,N′-pentamethyl-1,3-propylene,i.e. R is C₁₄₋₁₈-alkyl, X is propylene and R¹ to R⁵ is methyl.

The coloured acid may be any pigment or dyestuff which contains at leastone acid group. The acid group may be a carboxylic acid, phosphoric acidor preferably a sulphonic acid group which forms a salt with the diamineor diquaternary ammonium cation of formula 1. The coloured acid. may bederived from the same chromophore as the pigment or dyestuff to bedispersed. For example, when the pigment or dyestuff belongs to thephthalocyanine class of pigments, the coloured acid is preferably aphthalocyanine pigment containing one or more acid groups or a mixturethereof. Similarly, when the pigment or dyestuff is a disazo compoundobtainable by tetrazotising an aromatic diamine and reacting thetetrazonium ion with two moles of a coupling component which does notcontain an acid group, the coloured acid is preferably a similar pigmentor dyestuff wherein one or both the coupling components are the same asthat or those used to prepare the dyestuff or pigment except for thepresence of an acid group. In such circumstances it may be beneficial toprepare the fluidising agent in situ and concomitantly with thepreparation of the pigment or dyestuff. Such simultaneous preparation ofthe fluidising agent and pigment or dyestuff results in a morehomogenous mixture of the fluidising agent and pigment or dyestuffcompared with the separate preparation of the fluidising agent andsubsequent mixture with the dyestuff or pigment. When the fluidisingagent is derived from a coloured acid having a similar chromophore tothe pigment or dyestuff the shade of any resultant paint or printing inkhas the advantage that the presence of the fluidising agent does nothave a significant effect on colour.

As noted hereinbefore, the coloured acid may be any pigment or dyestuffwhich contains at least one acid group or a mixture of such pigments ordyestuffs.

In one preferred class of fluidising agents, the coloured acid is apolycyclic aromatic compound of the phthalocyanine series which containsone or more acid groups. The phthalocyanine may be halogenated, forexample, chlorinated but is preferably unhalogenated. The phthalocyaninemay also be unmetalised but is preferably in the form of its metalcomplex. Preferred metals are the transition elements in the PeriodicTable of Mendeleef as published for example on the inside rear page ofHandbook of Chemistry and Physics published by the Chemical RubberCompany, 49^(th) edition, Cleveland, Ohio, USA. Preferred metals aretitanium, iron, cobalt, nickel and especially copper. The coloured acidsof the phthalocyanine pigments are prepared in conventional manner suchas by heating in concentrated sulphuric acid or oleum until the requireddegree of sulphonation is achieved. Preferably, the phthalocyaninecoloured acid contains on average from 0.7 to 2.0, more preferably 1 to1.5 and especially from 1.15 to 1.25 sulphonic acid groups/mole.

In another preferred class of fluidising agents, the coloured acid is adisazo dyestuff comprising a central divalent group which is free fromacid and other ionic substituents which is linked through azo groups tocoupling components, the first of which is free from acid and otherionic substituents and the second carries one or more acid groups and isfree from other ionic substituents.

Preferably, the second coupling component carries only the one acidgroup.

The central divalent group is preferably a biphenylene group which maybe unsubstituted or substituted by one or more non-ionic groups.Examples of such groups are C₁₋₆-alkyl, C₁₋₆-alkoxy, halogen, nitro andcyano. When the substituent is alkyl, it is preferably methyl and whenthe substituent is alkoxy, it is preferably methoxy. When thesubstituent is halogen, it is preferably bromine and especiallychlorine.

Specific examples of the central divalent group are biphenylene,2,2′-dichlorobiphenylene, 3,3′-dimethoxybiphenylene,2,2′-dichloro-5,5′-dimethoxybiphenylene, 3,3′-dimethoxybiphenylene and3,3′-dimethylbiphenylene. In addition to the above substituents, thebiphenylene central divalent group may also carry an acetoacet-2-ylaminogroup in the 4,4′ positions such as4,4′-di(acetoacet-2-ylamino)-biphenyl and4,4′-di(acetoacet-2-ylamino)-3,3′-dimethylbiphenyl as found in ClPigment Yellow 16 and Pigment Yellow 77.

The first coupling component is preferably a pyrazolin-5-on-4-yl group,a 2-hydroxynaphth-1-yl group or an acetoacet-2-ylanilide group. Thefirst coupling component may carry other substituents which is not anacid or other ionic group such as C₁₋₆-alkyl, C₁₋₆-alkoxy, halogen,nitro, cyano, C₁₋₆-alkoxycarbonyl, phenylaminocarbonyl,naphthylaminocarbonyl and phenyl in which the phenyl and naphthyl groupsmay also be substituted by C₁₋₆-alkyl, C₁₋₆-alkoxy, nitro, halogen orcyano.

Specific examples of the first coupling component are residues offormula 2 to 4 below. In formulae 2 to 4, the coupling position isindicated by an unattached bond.

wherein R⁶, R⁷ and R⁸ are selected from H, C₁₋₆-alkyl, C₁₋₆-alkoxy,nitro and halogen, specific examples being shown in the following table.

R⁶ R⁷ R⁸ H H H —CH₃ —CH₃ H —CH₃ H H —OCH₃ H H H —CH₃ H —OCH₃ Cl —OCH₃ ClH H —OCH₃ H —OCH₃ H —OC₂H₅ H (3)

wherein R⁹ and R¹⁰ are selected from H, C₁₋₆-alkyl, C₁₋₆-alkoxy,halogen, nitro and C₁₋₆-alkoxy-carbonyl, specific examples being shownin the following table.

R⁹ R¹⁰ H —CH₃ —CH₃ —CH₃ H —CO₂C₂H₅ —NO₂ —CH₃ and (4)

wherein R¹¹ is H or a group of the formula:

wherein R¹² to R¹⁵ are selected from H C₁₋₆-alkyl, C₁₋₆-alkoxy, halogenand nitro, specific examples being shown in the following table.

R¹² R¹³ R¹⁴ R¹⁵ H H —CH₃ —CH₃ H H NO₂ H H Cl H H H —CH₃ H H H H H —CH₃ HH H —OCH₃ H H H —OC₂H₅ H Cl H —CH₃ Cl H —CH₃ H —OCH₃ H —OCH₃ H —OCH₃—OCH₃ Cl H

or R⁸ is of the formula:

The second coupling component of the disazo dyestuff which contains oneor more acid groups may be otherwise identical to the first couplingcomponent. Preferably, the second coupling component contains only theone acid group. The preferred second coupling components are, however,acetoacetanilides containing an acid group in the 4 position of thephenyl ring, 1-phenylpyrazolin-5-ones containing an acid group in the 4position of the phenyl ring and a 2-naphthyl group where the acid groupis in the 6-position.

In a further less preferred class of fluidising agent, the coloured acidis a disazo compound comprising a central divalent group which containsone or more acid groups and is free from other ionic substituents whichis linked through azo groups to two coupling components which mayoptionally contain one or more acid groups and where the acid groups arein the form of a salt of a diquaternary ammonium cation of formula 1.The central divalent group may additionally carry substituents asdisclosed hereinbefore and the coupling components, which may be thesame or different are also as described hereinbefore. Preferably, thecoupling components are both the same. It is also preferred that theacid group or groups in the central divalent group is a sulphonic acidgroup. Examples of such preferred central divalent groups arebiphenylene-2,2′-disulphonic acid and5,5′-dimethylbiphenylene-2,2′-disulphonic acid. Examples of othercentral divalent groups are biphenylene-2,2′-dicarboxylic acid and5,5′-dimethylbiphenylene-2,2′-dicarboxylic acid.

The fluidising agents may be made by any means known to the art such asreacting the coloured free acid either wholly or in part with thediamine and/or salt of a diquaternary ammonium compound or by reactingan alkali metal salt of the coloured acid with the halide or hydroxidesalt of the diamine and/or diquaternary ammonium compound. The formationof the coloured acid salts is typically carried out in water or a polarsolvent, including mixtures thereof and the fluidising agent isolated byconventional means such as filtration.

The amount of diamine and/or diquaternary ammonium compound to colouredacid may vary over wide limits. However, there is generally no advantagein having an excess of diamine and/or diquaternary ammonium compoundover the number of acid groups in the coloured acid. With somefluidising agents, such as those derived from a disazo coloured acidcontaining only one acid group, it may be advantageous for all the acidgroups in the fluidising agent to be in the form of the diamine and/ordiquaternary ammonium salts. With other fluidising agents it may bepreferable to use less diamine and/or diquaternary ammonium compoundrelative to the number of acid groups. Where the fluidising agentcontains acid groups other than those in the form of a salt with thediamine and/or diquaternary ammonium compound, those acid groups may bein the form of the free acid or salt of an alkali or alkali earth metal.Where the coloured acid is a polycyclic compound of the phthalocyanineclass of pigments, useful fluidising agents have been obtained where notgreater than 80%, and especially not greater than 60% of the acid groupshave been converted to the salt form of the diamine and/or diquaternaryammonium compound. Preferably the amount of diamine and/or diquaternaryammonium compound to acid groups in the phthalocyanine coloured acid isnot less than 20% and especially not less than 30%.

Where the coloured acid is an azo or disazo dyestuff it may be preparedby any means known to the art and especially those processes describedin GB 1,356,253 and U.S. Pat. No. 4,461,647. Thus, for example, anaromatic amine may be diazotised or an aromatic diamine may betetrazotised and reacted with a coupling component or components underneutral or alkaline conditions in aqueous media to form a coloured acidcontaining one or more acid groups. The acid groups may be converted, atleast in part, to the salt of the diamine and/or diquaternary ammoniumcompound as disclosed hereinbefore. The azo or disazo coloured acid maycontain a mixture of acid groups in the form of a salt of the diamineand/or diquaternary ammonium compound and also an acid group in the formof its free acid or salt with an alkali metal or alkaline earth metal.Preferably, the acid groups are substantially in the form of the saltwith the diamine and/or diquaternary ammonium compound, especially wherethe coloured acid is a disazo dyestuff.

In certain instances, it may be advantageous to prepare the fluidisingagent concomitantly with the pigment. This is particularly preferredwhere the coloured acid is a disazo dyestuff, especially that containinga biphenylene central divalent group, and the pigment has a similarstructure which is free from acid or other ionic groups.

Thus, according to a further aspect of the invention there is provided acomposition comprising a fluidising agent and a pigment.

Preferably, the pigment has a similar chemical structure to the colouredacid of the fluidising agent but is free from acid or other ionicgroups.

In one preferred aspect, there is provided a composition comprising aphthalocyanine pigment and a fluidising agent which is a phthalocyaninedyestuff containing one or more acid groups in the form of a salt with adiamine and/or diquaternary ammonium cation of formula 1. Preferably,the phthalocyanine pigment and phthalocyanine dyestuff are metalphthalocyanines containing nickel or preferably copper.

In another preferred aspect there is provided a composition comprisingan azo or disazo pigment and a fluidising agent which is an azo ordisazo coloured acid containing one or more acid groups in the form of asalt with a diamine and/or diquaternary ammonium cation of formula 1. Itis preferred that the pigment and coloured acid are either both azocompounds or both disazo compounds.

When the pigment and coloured acid are both disazo compounds and thefluidising agent is prepared concomitantly with the pigment, thecoloured acid and hence fluidising agent may be a mixture as discussedhereinafter.

According to another aspect of the invention, there is provided a disazocomposition comprising at least 30%, by weight, of an asymmetricfluidising agent which is a water insoluble disazo coloured acid whereina central divalent group which is free from acid and other ionic groupsis linked through azo groups to coupling components, the first of whichis free from acid or other ionic groups and the second carries one ormore acid groups in the form of a diquaternary ammonium cation offormula 1.

A preferred composition according to the invention contains anasymmetric compound of formula

Y—B—A—B—Z

wherein

A is selected from biphenylene, 3,3′-dichlorobiphenylene,3,3′-dimethylbiphenylene, 3,3′-dimethoxybiphenylene and2,2′-dichloro-5,5′-dimethoxybiphenylene;

both B components are either azoacetoacetamide groups of formula

Y is selected from pyrazolin-5-on-4-yl, 2-hydroxynaphth-1-yl and2-hydroxy-3-carbonylaminophenylnaphth-1-yl which may be substituted byone or more groups selected from C₁₋₆-alkyl, C₁₋₆-alkoxy, halogen, nitroand C₁₋₆-alkoxycarbonyl and when B is azoacetoacetamido Y is phenyl orphenyl substituted by one or more groups selected from C₁₋₆-alkyl,C₁₋₆-alkoxy, halogen and nitro; and

Z is selected from the same groups as Y except that it carries an acidgroup in the form of a salt of a diquaternary ammonium cation of formula1 in addition to or in place of one of the substituents already on Y.

As disclosed hereinbefore, it may be advantageous to prepare thefluidising agent and pigment simultaneously, especially where thepigment and coloured acid are both disazos and especially disazos of thebenzidine class of colourants. In this case, the composition is amixture of disazo compounds of formulae

Y—B—A—B—Z

Y—B—A—B—Y

Z—B—A—B—Z

Preferably, the composition comprises at least 35% and especially atleast 40%, by weight, of the asymmetric fluidising agent. It is alsopreferred that the composition comprises not greater than 70%, morepreferably not greater than 65% and especially not greater than 60%, byweight, of the asymmetric compound. It is especially preferred that thecomposition contains from 50 to 60%; by weight, of the asymmetriccompound.

In some instances it may be beneficial to provide the fluidising agentin an organic liquid. Hence, according to a further aspect of theinvention there is provided a composition comprising an organic liquidand the fluidising agent.

As noted hereinbefore, the fluidising agents according to the inventionare particularly useful in providing a dispersion of a pigment in anorganic liquid which exhibits enhanced fluidity, especially at highpigment loading. Thus, according to a further aspect of the inventionthere is provided a dispersion comprising a pigment, dispersant,fluidising agent and organic liquid.

The pigment may be from any of the recognised classes of pigmentsdescribed, for example, in the Third Edition of the Colour Index (1971)and subsequent revisions of, and supplements thereto, under the chapterheaded “Pigments”. The pigment may be inorganic or organic. Examples ofinorganic pigments are titanium dioxide, zinc oxide, Prussian blue,cadmium sulphide, iron oxides, vermillion, ultramarine and the chromepigments, including chromates, molybdates and mixed chromates andsulphates of lead, zinc, barium, calcium and mixtures and modificationsthereof which are commercially available as greenish-yellow to redpigments under the names primrose, lemon, middle, orange, scarlet andred chromes. Examples of organic pigments are those from the azo,disazo, condensed azo, thioindigo, indanthrone, isoindanthrone,anthanthrone, anthraquinone, isodibenzanthrone, triphendioxazine,quinacridone and phthalocyanine series, especially copper phthalocyanineand its nubclear halogenated derivatives, and also lakes of acid, basicand mordant dyes. Carbon black, although strictly inorganic, behavesmore like an organic pigment in its dispersing properties. Preferredorganic pigments are phthalocyanines, especially copper phthalocyanines,monoazos, disazos, indanthrones, anthanthrones, quinacridones and carbonblacks.

The dispersant is preferably a resinous or polymeric material which ismixed with the pigment to uniformly distribute the pigment throughoutthe organic liquid. Preferred dispersants are obtainable by reactingpolyester chains with amines, polyamines or polyimines to form amideand/or salt linkages or dispersants containing polyester chains reactedwith polyisocyanates containing from 2 to 10 isocyanate groups. Thepolyester chain may be derived from a single hydroxycarboxylic acidcontaining an alkylene or alkenylene chain or a mixture ofhydroxycarboxylic acids, including lactones thereof. Preferredhydroxycarboxylic acids contain from 6 to 20 carbon atoms between thehydroxy group and the carboxylic acid group. Examples of suitablehydroxycarboxylic acids are ricinoleic, 12-hydroxystearic,12-hydroxydodecanoic, 5-hydroxydodeconoic, 5-hydroxydecanoic and4-hydroxydecanoic acids. Suitable lactones are ε-caprolactone optionallysubstituted by C₁₋₆-alkyl groups and δ-valerolactone. The polyesterchain may also carry a polymerisation terminating group which is derivedfrom a carboxylic acid which is free from hydroxy groups. Examples ofsuch acids are stearic and lauric acids.

The amine, polyamine or polyimine from which the dispersant is derivablehas a preferred number average molecular weight between 100 and 500,000.The amine may be relatively small, such as dimethylaminopropylamine orit may be relatively large such as polyvinylamine, polyallylamine orC₂₋₆-polyalkyleneimine, for example polyethyleneimine. Any free aminegroups in the dispersant may optionally be converted to quaternaryammonium groups by reaction with alkyl halides or dialkylsulphates suchas methyl bromide or dimethylsulphate.

Preferred dispersants are those derivable from polyhydroxystearic acidas disclosed, for example, in U.S. Pat. No. 3,996,059.

The organic liquid may be either polar or preferably substantiallynon-polar.

By the term “polar” in relation to the organic liquid is meant anorganic liquid or resin capable of forming moderate to strong bonds asdescribed in the article entitled “A Three Dimensional Approach toSolubility” by Crowley et al in Journal of Paint Technology, Vol. 38,1966, at page 269. Such organic liquids generally have a hydrogenbonding number of 5 or more as defined in the above mentioned article.

Examples of suitable polar organic liquids are amines, ethers,especially lower alkyl ethers, organic acids, esters, ketones, glycols,alcohols and amides. Numerous specific examples of such moderatelystrongly hydrogen bonding liquids are given in the book entitled“Compatibility and Solubility” by Ibert Mellan (published in 1968 byNoyes Development Corporation) in Table 2.14 on pages 39-40 and theseliquids all fall within the scope of the term polar organic liquid asused herein.

Preferred polar organic liquids are dialkyl ketones, alkyl esters ofalkane carboxylic acids and alkanols, especially such liquids containingup to, and including, a total of 6 carbon atoms. As examples of thepreferred and especially preferred liquids there may be mentioneddialkyl and cycloalkyl ketones, such as acetone, methyl ethyl ketone,diethyl ketone, di-isopropyl ketone, methyl isobutyl ketone, di-isobutylketone, methyl isoamyl ketone, methyl n-amyl ketone and cyclohexaonone;alkyl esters such as methyl acetate, ethyl acetate, isopropyl acetate,butyl acetate, ethyl formate, methyl propionate, methoxy propylacetateand ethyl butyrate; glycols and glycol esters and ethers, such asethylene glycol, 2-ethoxyethanol, 3-methoxypropylpropanol,3-ethoxypropylpropanol, 2-butoxyethyl acetate, 3-methoxypropyl acetate,3-ethoxypropyl acetate and 2-ethoxyethyl acetate; alkanols such asmethanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol anddialkyl and cyclic ethers such as diethyl ether and tetrahydrofuran.

The substantially non-polar organic liquid which may be used alone or inadmixture with the polar organic liquid may be aliphatic or aromatic andmay be substituted by halogens such as chlorine. Examples of aliphatichydrocarbons are heptane, octane, nonane and the high boiling aliphaticdistillates such as white spirits. Examples of aromatic organic liquidare toluene and xylene. Examples of halogenated organic liquids aremonochlorobenzene, dichlorobenzene, trichlorobenzene, trichloroethaneand parchloroethylene.

Preferably, the organic liquid is a non-polar organic liquid and isespecially toluene, xylene or a high boiling aliphatic distillate suchas white spirits.

Examples of suitable polar resins, as the organic liquid for thedispersion form of the present invention, are film-forming resins suchas are suitable for the preparation of inks, paints and chips for use invarious applications such as paints and inks. Examples of such resinsinclude polyamides, such as Versamid™ and Wolfamid™, and celluloseethers, such as ethyl cellulose and ethyl hydroxyethyl cellulose.Examples of paint resins include short oil alkyd/melamine-formaldehyde,polyester/melamine-formaldehyde, thermosettingacrylic/melamine-formaldehyde, long oil alkyd and multi-media resinssuch as acrylic and urea/aldehyde.

The dispersion may be made by any means known to the art. Thus, theparticle size of the pigment may be reduced by attrition processes suchas grinding or milling preferably in the presence of the dispersant andorganic liquid. The fluidising agent may be added at any stage,including addition to the final dispersion. However, it is preferred toadd the fluidising agent prior to the attrition process. Preferably, theparticle size of the pigment is reduced to less than 10μ, morepreferably less than 3μ and especially less than 1μ. The attritionprocess is normally carried out at 20 to 25° C. However, with certainpigments it may be beneficial to carry out the attrition process at 50to 150° C. in a non-polar organic liquid which is, or contains, a highboiling aliphatic distillate. This is particularly true where thepigment and coloured acid of the fluidising agent belong to thephthalocyanine class and where such high temperature attrition processcan result in greener and brighter shades in the final printing ink orpaint.

The dispersion preferably contains from 5% to 70%, by weight, pigmentbased on the total amount of the dispersion and from 1% to 50%, byweight, of fluidising agent and from 3% to 50%, by weight of dispersant,both latter amounts being based on the amount of pigment. It isespecially preferred that the amount of pigment is from 25% to 60% ofthe dispersion and the amount of fluidising agent is from 5% to 15% andthe amount of dispersant is from 10% to 30%, both on amount of pigment,respectively.

The fluidising agent may be used in the preparation of millbases wherethe dispersion additionally comprises a film-forming resin and theattrition process is preferably carried out with the film-forming resinpresent. Typically, the millbase contains from 20 to 70%, by weight,pigment based on the amount of millbase. Preferably, the amount ofpigment is not less than 30% and especially not less than 50%. Theamount of film-forming resin may vary over wide limits but is preferablynot less than 10% and especially not less than 20% of thecontinuous/liquid phase of the millbase. Preferably, the amount of resinis not greater than 50% and especially not greater than 40%, by weight,of the continuous/liquid phase of the millbase. The amount of dispersantand fluidising agent in the millbase relative to the amount of pigmentis as disclosed for the dispersion.

The dispersion and millbase can contain other adducts which are commonlyadded to paints and printing inks such as humectants, fillers,cross-linkers and preservatives.

The dispersions and millbases containing the fluidising agent areparticularly useful for preparing printing inks and paints, especiallyhigh solid containings paints and inks, especially flexographic, gravureand screen inks.

The dispersions and millbases may also be used to prepare tinter inksand paints which comprise a base pigment and a tinter pigment. The basepigment is preferably ferric oxide and especially titanium dioxidedispersed in a non-polar organic liquid and the coloured tinter pigmentis added which is dispersed in a polar organic liquid such as ethyleneglycol and/or water. Preferably, the amount of tinter pigment is notgreater than 10% and especially not greater than 3%, by weight, based onthe amount of base pigment. It is also preferred that the amount ofpolar liquid and/or water is not greater than 30% and especially notgreater than 10%, by weight, based on the non-polar liquid.

The invention is further illustrated by the following examples whereinall references are to parts by weight unless expressed to the contrary.

Examples 1 and 2

Blue Fluidising Agents

Copper phthalocyanine (CuPc 31.62 parts) was added slowly to 20% oleum(139.75 parts) with stirring at 38° C. The temperature was raised to 50°C. and stirring continued to thoroughly disperse the CuPc. Thetemperature was then raised to 65° C. and stirring continued to effectsulphonation. When the requisite sulphonation had been obtained, thereaction mix was drowned out into cold water (550 parts). The productwas filtered and washed with progressively decreasing strength ofhydrochloric acid (1% to 0.1%) to give a paste of sulphonated CuPc in0.1% acid. Water (200 parts) was added to the paste which was thenstirred at 70° C. prior to adding tallowpentamethylpropylenediammoniumhydrochloride as a 50% solution in isopropanol (Duoquad T50 ex. Akzo).The reaction mix was stirred for a further 1 hour at 70° C., filteredhot, washed with water and dried.

A dispersion was prepared containing CuPc pigment (14.4 parts, LutetiaBlue ENJ ex. BASF), amine dispersant (1.8 parts, Solsperse 17000 ex.Avecia), fluidising agent (0.4 parts), toluene (23.4 parts) and glassbeads (3mm diameter, 150 parts). The dispersion was shaken on a RedDevil Shaker for 30 minutes and then separated from the beads. Theviscosity was measured using a Bohlin Viscometer and also assessedvisually using an arbitrary scale of A to E (very fluid to extremelyviscous). The results are given in Table 1 below.

TABLE 1 Degree of Arbitrary Example Fluidising Agent Sulphonation % SaltViscosity 1 1 1.2 60 B 2 2 1.7 40 B A A 1.2 40 E B B 1.7 40 D C C 1.2 60E D D 1.7 60 D E E 2.0 50 C F F 1.3 50 C Footnote to Table 1 Fluidisingagents A, B and C were prepared using Arquad 2C-75(N,N-didodecyl-N,N-dimethyl ammonium chloride). Fluidising Agents A isAgent A of U.S. Pat. No. 4,057,436 and Fluidising Agents B and C weremade by analogous methods. Fluidising agent D was prepared usingN-octadecyl-N,N,N-trimethyl ammonium chloride. Fluidising Agents E and Fwere prepared using N,N-dioctadecyl-N,N-dimethyl ammonium chloride.Fluidising Agent E is Agent C of U.S. Pat. No. 4,057,436 and FluidisingAgent F is Agent B of U.S. Pat. No. 4,057,436.

Examples 3 to 11

Examples 1 and 2 were repeated except the degree of sulphonation and %salt conversion of the sulphonic acid groups of the copperphthalocyanine is as indicated in Table 2 below.

In Table 2, different quaternary ammonium cations were examined ofgeneral formula

TABLE TWO Example Fluidising Agent R¹ R⁶ X % Salt DOS ArbitraryViscosity  3  3 C₁₂ C₁₂ —CH₂CH═CHCH₂— 60 0.6 C  4  4 C₁₈ C₁₈ —(CH₂)₄— 400.6 B  5  5 C₁₈ C₁₈ —CH₂CH═CHCH₂— 60 1.7 C  6  6 C₁₂ C₁₂ —(CH₂)₄— 40 1.7C  7  7 C₁₈ C₁₈ —(CH₂)₆— 60 1.2 B  8  8 C₁₂ C₁₂ —(CH₂)₆— 60 1.2 B  9  9C₁₈ C₁ —(CH₂)₃— 90 1.2 B 10 10 C₁₈ C₁ —(CH₂)₃— 60 0.8 B 11 11 C₁₈ C₁—(CH₂)₃— 40 1.7 A C — — — 60 1.2 E F — — — 50 1.3 C Footnote to Table 2Data in columns R¹ and R⁶ indicate the number of carbon atoms in thesaturated aliphatic chain.

DOS is the degree of sulphonation.

Examples C and F utilise Comparative Agents C and F, respectively, whichare explained in the footnote to Table 1.

Example 12

Pyrazolone Disazo Yellow Fluidising Agent

a) Preparation of Dyestuff

3,3¹-Dichlorobenzidine dihydrochloride (10 parts, 0.0306 M ex sigma) wasstirred in water (100 parts). Concentrated hydrochloric acid (10 ml) wasadded and the volume adjusted to 300 ml by addition of water. Thediamine was tetrazotised by dropwise addition of sodium nitrite (6parts) dissolved in water (20 ml) and stirring for 1 hour at 0° C.

Excess nitrous acid was destroyed by addition of sulphamic acid.3-methyl-1-phenyl-2-pyrazolin-5-one (6.41 parts, 0.0368M ex Acros) and3-methyl-1-(4-sulphophenyl)-2-pyrazolin-5-one (9.36 parts, 0.0368M exAcros) were added to water (50 ml) and the pH adjusted to 9-9.5 byaddition of caustic soda solution to dissolve the pyrazolones. This wasthen diluted to 400 ml by addition of water and the tetrazotised diamineadded with stirring at <5° C. and maintaining a pH of 8.5 by addition ofalkali. After stirring for 1 hour the temperature was raised to 90° C.and the reaction mix was stirred for a further 1 hour at 90° C. Aftercooling, the pH was adjusted to 3 and the yellow dyestuff was filtered,washed with hot water and dried at 90° C. to give an orange solid (23parts).

b) Preparation of Decamethonium Salt

[—(CH₂)₅N⁺(CH₃)₃]₂

The disazo dyestuff (2 parts, 0.003M) was dissolved in water (60 ml) andisopropanol (20 mls) by stirring at 75° C. Decamethonium bromide (0.87parts ex Aldrich) was added with stirring at 75° C. After cooling, theproduct was filtered, washed with water and dried at 75° C. to give anorange solid (2.6 parts). This is Fluidising Agent 12.

Comparative Example G

Example 12b) was repeated except replacing the decamethonium bromidewith N,N-didodecyl-N,N-dimethyl ammonium chloride (1.16 parts, Arquad 2Cex Akzo) to give an orange solid (2.5 parts). This is Fluidising AgentG.

Example 13

Acetoacetarylamide Disazo Yellow Fluidising Agent

a) Preparation of Dyestuff

3,3¹-Dichlorobenzidine dihydrochloride (5.33 parts, 0.0163 M ex Sigma)was stirred with water (50 ml) and then concentrated hydrochloric acid(5 ml) and water (100 ml) was added. After stirring at 20° C. for 16hours, the diamine solution was cooled to 0° C. and tetrazotised by thedropwise addition of sodium nitrite (3 parts) dissolved in water (10ml). After stirring at 0° C. for a further 1 hour excess nitrite asremoved by addition of sulphamic acid.

A coupling bath was prepared by dissolving acetoacetanilide (3.91 parts,0.0221M ex Acros) and potassium N-acetoacetylsulphanilate (6.51 parts,0.0220M ex Lonza) in water (100 parts) and caustic liquor (4.5 ml) at40° C. After cooling to 20° C, concentrated hydrochloric acid (2.5 ml)and acetic acid (2 ml) was added to the coupling bath and followed byaddition of the tetrazo solution with stirring below 5° C. andmaintaining a pH of 4.5 by addition of sodium acetate. Finally, the pHwas adjusted to 3 and the dyestuff filtered, washed with hot water anddried at 90° C. to give an orange solid (15 parts).

b) Preparation of Duoquad Salt

Disazo orange solid (2 parts) was stirred in water (60 ml) andisopropanol (20 ml) at 75° C. The diquaternary ammonium chloride (1.66parts as a 50% solution in isopropanol, Duoquad T50, ex Akzo.) was addedand stirred for 1 hour at 75° C. After cooling, the dye salt wasfiltered, washed with water and dried at 75° C. to give an orange/yellowsolid (2.6 parts). This is Fluidising agent 13.

c. Preparation of Decamethonium Salt

[—(CH₂)₅N⁺CH₃)₃]₂

Example 13b) was repeated except using decamethonium bromide (0.86parts) in place of the Duoquad T50. This is Fluidising Agent 14.

Comparative Example H

Example 13b) was again repeated except using N,N-didodecyl-N,N-dimethylammonium chloride (1.15 parts as a 75° C. solution isopropanol, Arquad2C ex Akzo) This is Fluidising Agent H.

Example 14

Naphthol Disazo Red Fluidising Agent

a) Preparation of Dyestuff

Example 12a) was repeated except using a coupling mixture of 2-naphthol(5.35 parts, 0.0371 m ex Aldrich) and sodium-2-hydroxy-6-naphthalenesulphonate (9.14 parts, 0.0407 m ex Avecia ). The dyestuff was obtainedas a purple solid (20 parts).

b) Preparation of Duoquad salt

Disazo dyestuff (2 parts) was stirred in water (60 ml) and isopropanol(20 parts) at 75° C. The diquaternary ammonium chloride (1.84 parts as50% solution in isopropanol, Duoquad T50 ex Akzo) was added and thereactants were stirred at 75° C. for 1 hour. After cooling, the productwas filtered, washed with hot water and dried at 75° C. to give a purplesolid (2.7 parts). This is Fluidising Agent 15.

Comparative Example

Example 14b) was repeated except using N,N-didodecyl-N,N-dimethylammonium chloride (1.28 parts as a 75% solution in isopropanol, Arquad2C ex Akzo). Fluidising Agent I was obtained as a purple solid (2.8parts).

Examples 15 and 16

A dispersion was prepared by milling yellow pigment (2 parts, IrgaliteYellow BW ex Ciba Geigy), amine dispersant (0.4 parts, Solsperse 17000ex Avecia), fluidising agent (0.1 part) and aliphatic solvent (Paraset29L ex Carless Refining Ltd) in the presence of 3 mm diameter glassbeads (17 parts) on a horizontal shaker for 30 minutes. The viscosity ofthe resultant dispersion was assessed by hand shaking using an arbitraryscale of A to E (low viscosity to high viscosity). The results are givenin Table 2 below and show that the fluidising agent prepared with adiquaternary ammonium cation exhibit superior viscosity to thoseprepared using a monoquaternary ammonium cation.

TABLE 2 Example Fluidising Agent Viscosity 15 15 C/D I D 16 12 C/D G D

Examples 17 and 18

Examples 15 and 16 were repeated except using amine dispersant (0.45parts, Solsperse 17000), fluidising agent (0.25 parts) and toluene (7.3parts). The results are given in Table 3 below and again show thesuperior viscosity of dispersions prepared using a fluidising agentwhich is a diquaternary ammonium salt.

TABLE 3 Example Fluidising Agent Viscosity 17 13 C 18 14 C J C/DFluidising Agent J is Example 1 of GB 2,108,143 (monoquaternary ammoniumsalt)

What is claimed is:
 1. A fluidising agent which is a diquaternaryammonium salt of a coloured acid wherein the diquaternary ammoniumcation contains two or more nitrogen atoms.
 2. A fluidising agent asclaimed in claim 1 wherein the diquaternary ammonium cation is offormula 1

wherein R is optionally substituted C₆₋₃₀-alkyl or optionallysubstituted C₆₋₃₀ alkenyl; R¹ is optionally substituted C₁₋₃₀-alkyl orC₂₋₃₀-alkenyl, optionally substituted cycloalkyl, optionally substitutedaryl or optionally substituted aralkyl; R², R³, and R⁵ are each,individually, optionally substituted C₁₋₆-alkyl, optionally substitutedcycloalkyl, optionally substituted aryl or optionally substitutedaralkyl; R⁴ is optionally substituted C₁₋₆-alkyl, optionally substitutedcycloalkyl, optionally substituted aryl or optionally substitutedaralkyl; X is C₁₋₁₂-alkylene; or R¹ and R³ together with the twonitrogen atoms to which they are attached and X form a ring; and/or R⁴and R⁵ together with the nitrogen atom to which they are attached form aring.
 3. A fluidising agent as claimed in claim 2 wherein R isC₆₋₃₀-alkyl and/or C₆₋₂₀-alkenyl and R¹ to R⁵ are each, independently,C₁₋₆-alkyl.
 4. A fluidising agent as claimed in claim 2 wherein thetotal number of carbon atoms represented by R to R⁵ and X is not greaterthan
 80. 5. A fluidising agent as claimed in claim 2 wherein X isalkylene containing not less than 2 and not greater than 12 carbonatoms.
 6. A fluidising agent as claimed in claim 1 wherein the colouredacid is a phthalocyanine which contains one or more acid groups.
 7. Afluidising agent as claimed in claim 6 wherein the phthalocyaninecontains on average from 1 to 1.5 sulphonic acid groups/mole.
 8. Afluidising agent as claimed in claim 6 wherein not greater than 80% andnot less than 20% of the acid groups are in the form of a diquaternaryammonium salt.
 9. A fluidising agent as claimed in claim 1 wherein thecoloured acid is a disazo dyestuff comprising a central divalent groupwhich is free from acid and other ionic substituents which is linkedthrough azo groups to first and second coupling components, the firstcoupling component is free from acid and other ionic substituents andthe second coupling component carries one or more acid groups and isfree from other ionic substituents.
 10. A fluidising agent as claimed inclaim 9 wherein the central divalent group is a biphenylene group whichmay be unsubstituted or substituted by one or more non-ionic groups. 11.A fluidising agent as claimed in claim 10 wherein the non-ionic group isC₁₋₆-alkyl, C₁₋₆-alkoxy, halogen, nitrogen or cyano.
 12. A fluidisingagent as claimed in claim 9 wherein the first coupling component is apyrazolin-5-on-yl group, a 2-hydroxy-naphth-1-yl group or anacetoacet-2-ylanilide group which may be substituted by C₁₋₆-alkyl,C₁₋₆-alkoxy, halogen, nitro, cyano, C₁₋₆-alkoxycarbonyl,phenylaminocarbonyl, naphthylaminocarbonyl and phenyl in which thephenyl and naphthyl groups may also be substituted by C₁₋₆-alkyl,C₁₋₆-alkoxy, nitro, halogen or cyano.
 13. A fluidising agent as claimedin claim 9 wherein the second coupling component contains one or moreacid groups but is otherwise identical to the first coupling component.14. A fluidising agent as claimed in claim 1 wherein the coloured acidis a disazo dyestuff comprising a central divalent group which containsone or more acid groups and where the acid groups are in the form of asalt of a diquaternary ammonium cation.
 15. A composition comprising anorganic liquid and a fluidising agent as claimed in claim
 1. 16. Acomposition comprising a pigment and a fluidising agent as claimed inclaim
 1. 17. A composition as claimed in claim 16 wherein the pigment isa phthalocyanine or disazo pigment.
 18. A dispersion comprising apigment, organic liquid, dispersant and a fluidising agent as claimed inclaim
 1. 19. A dispersion as claimed in claim 18 wherein the dispersantis obtained by reacting polyester chains with amines, polyamines orpolyimines to form amide and/or salt linkages.
 20. A dispersion asclaimed in claim 19 wherein the polyester chain is derived from ahydroxycarboxylic acid containing from 6 to 20 carbon atoms between thehydroxy and carboxylic acid groups.
 21. A dispersion as claimed in claim18 wherein the organic liquid is substantially non-polar.
 22. A millbasecomprising a pigment, organic liquid, dispersant, film-forming resin anda fluidising agent as claimed in claim
 1. 23. A paint or printing inkcomprising a pigment, dispersant, film-forming resin and a fluidisingagent as claimed in claim 1.